Tynan, you have my utmost respect for your dedication and your hard work. However, ultimately, the only metric for your success won't be your faith, but how many people will give you actual money for the product.
You've got your first dozen paying customers and some people would say that this is enough as a business/market evaluation. Congrats for that achievement!
Investing two years in a product without having a single paying customer has quite some risk and cost attached to it. I'm not sure if I'd do it. Not only is there the cost of "missed opportunity to make cash otherwise" but also the possibility that not enough people will buy, which might be the worst case. Some people are paying, but not enough to be sustainable. This would be different if you invested only a couple hundred hours and see if you can make a few bucks of it. But a couple thousand hours?
With that investment comes also a huge emotional investment. You made sacrifices throughout the two years and with that there's an increase of the feeling that "It HAS to work - otherwise, I'm crushed deeply". But I guess from what I've learned about you from your blog post, this is exactly the way you wanted it. High risk, hopefully high reward. Sort of extreme.
Anyways, I wish you all the best with SETT!